1. Field of the Invention
The present invention relates to a liquid pressure generating apparatus including a pump having a pump case and a pump drive shaft, and two one-way clutches arranged coaxially with the pump drive shaft in a line in the axial direction on the side of a first axial direction, which is one side of the pump drive shaft, with respect to the pump case, and a driving apparatus having the corresponding liquid pressure generating apparatus.
2. Description of the Related Art
As an example of a hydraulic pressure generating apparatus in the related art as an example of the above-described liquid pressure generating apparatus, for example, there are hydraulic pressure generating apparatuses described in JP-A-10-67238 and JP-A-2003-336725 described below. More specifically, in both JP-A-10-67238 and JP-A-2003-336725, a configuration in which two one-way clutches are arranged in such a manner that the restricted directions of relative rotation of an outer race with respect to an inner race (hereinafter, referred to as “target direction” in the description of the background art) are identical to each other, and the inner races of both one-way clutches are both coupled to a pump drive shaft is disclosed. Accordingly, when only the outer race of one of the two one-way clutches is rotated in the above-described target direction, an oil pump is driven by the rotation of the corresponding one of the outer races. When the outer races of both of the two one-way clutches rotate in the above-described target direction, the oil pump is driven by the rotation of the outer race rotating at a higher rotational speed from between the corresponding two outer races.
Also, in both JP-A-10-67238 and JP-A-2003-336725, a configuration in which the hydraulic pressure generating apparatus as described above is provided in a driving apparatus for a hybrid vehicle which is capable of traveling using both of an internal combustion engine and a dynamo-electric machine as driving power sources is disclosed. Specifically, a configuration is such that the outer race of one of the one-way clutches and the internal combustion engine are drive-coupled, and the outer race of the other one-way clutch and the dynamo-electric machine are drive-coupled. Accordingly, the oil pump is driven by a torque of the internal combustion engine or the dynamo-electric machine according to the traveling state of the vehicle and so that oil can be supplied to a portion requiring oil adequately.
Incidentally, in the configuration in which the inner races of both of the two one-way clutches are coupled to the pump drive shaft as described above, it is necessary to secure supporting accuracy of the pump drive shaft to an extent which can preferably secure liquid tightness and durability of the pump, or function and durability of the one-way clutches. Also, the supporting accuracy of the pump drive shaft is preferably secured in a mode in which upsizing of the liquid pressure generating apparatus is restrained.
However, in JP-A-10-67238 and JP-A-2003-336725 above-described, there is no description about the supporting accuracy of the pump drive shaft. Therefore, in JP-A-10-67238 and JP-A-2003-336725 above-described, there is no description about the securement of the supporting accuracy of the pump drive shaft in the mode in which upsizing of the liquid pressure generating apparatus is restrained as a matter of course, and a configuration in which the supporting accuracy of the pump drive shaft is adequately secured while restraining upsizing of the liquid pressure generating apparatus is not yet known.